The invention relates to a trimmer apparatus that trims book forms made on a bindery apparatus. The latter has a large number of signature feeding machines (hereinafter called "pocket machines") which feed individual folded sheets or signatures to a gathering conveyor. The gathering conveyor passes beneath the pocket machines and collects the folded sheets which are deposited on a triangular saddle with laps on opposite sides of the saddle. The gathering conveyor receives a systematic superimposition of sheets from the respective pocket machines to create a multi-signature book form. The book form is conveyed on the saddle into and through a stitching machine that stitches the book forms by stapling the book forms with staples. After stapling, the book forms are transported to a trimmer machine which severs the face and sides of the stapled book form.
Such binding apparatus operates at very high production speeds, e.g., 5,000 to 18,000 book forms per hour with the signatures and book forms continuously traveling at high speeds. The number of signatures in a book form varies from a few to a large number--e.g., eighteen (18) signatures or more. Likewise, the number of pages in one signature varies from one to several pages. The size dimensions of the signatures varies from job to job, and the trimmer machine must be reset and properly timed when changing from one size of signature to another size of signature. Currently, the operators of such bindery apparatus are skilled persons who have been trained over an extensive period of time of how to make ready the bindery apparatus for a particular job and then to do initial production runs which require fine adjustments or tweaking of the machines and conveyors to obtain the full production rate of operation of the bindery apparatus. The time used for make-ready and for initial production tweaking is currently very substantial. For example, a typical make-ready operation may take four to twelve (12) or more hours, and the initial production runs with tweaking may last one to twenty-four (24) hours before full production speed is obtained. During the make-ready and initial production runs, the bindery apparatus including the trimmer machine is run with signatures many of which become scrap. It is not uncommon for as much as one-half of one percent of a production run to become scrap during the make-ready and initial production runs.
If a bindery apparatus is not making a production run, it is not making signature book forms; so that a make-ready time of twelve (12) hours will mean twelve (12) hours of lost production. If the production rate is 10,000 book forms per hour, then the production of 120,000 book forms is lost during the twelve hours of make-ready. Also, if the scrap generated is 1,000 book forms, by way of example, then the cost of paper and printing is another significant expense.
The trimmer machine presents problems in make-ready because the scales and other information provided are not very accurate or becomes so inaccurate over a period of time that the scales are no longer used by the operator. For instance, a rotary scale provided at hand wheel for shifting the head and face knives becomes so inaccurate with time that operators use a tape measure to measure the distance between the head and foot knives, rather than using the rotary scale. Likewise, a rotary scale at the hand wheel to adjust the distance between the face stops which engage the fold of the book form and a face cut knife to trim the face become so inaccurate because the face cut knife is sharpened, gears become worn, or play such as backlash occurs, that the operators again use a tape measure rather than the rotary scale. A third rotary scale is provided for timing of the face cut knife operation to the lugs on the infeed conveyors, and for the same reasons, the scale is useless except as a general guide. The operators place sample book forms on the infeed conveyors and adjust the position of the face cut knife to obtain the desired timing. The trimmer is subject to various time-consuming and difficult to make measurements for its use. These operations require machine jogging to test. Also, this results in maladjustments at the trimming machine that require tweaking to correct.
From the foregoing, it will be seen that there is a need for a new and improved method of make-ready of a trimmer machine used in a bindery system. Among these needs is a substantial reduction in variations due to the subjective judgment of operators, in the time lost in tweaking, and in the scrap generated. Further, there is a need to reduce the make-ready time so that the trimmer machine as well as the other components of bindery apparatus are utilized to a greater extent at full production speed than has been done heretofore.